Ticket #61: Implement SRTP support in PJMEDIA and PJSUA-LIB, and updated applications because of the changes. This is a major modification back ported from SRTP branch. See ticket #61 for changelog detail of this commit

git-svn-id: https://svn.pjsip.org/repos/pjproject/trunk@1735 74dad513-b988-da41-8d7b-12977e46ad98
diff --git a/pjsip/include/pjsua-lib/pjsua_internal.h b/pjsip/include/pjsua-lib/pjsua_internal.h
index 943eb69..261cea0 100644
--- a/pjsip/include/pjsua-lib/pjsua_internal.h
+++ b/pjsip/include/pjsua-lib/pjsua_internal.h
@@ -50,7 +50,8 @@
     int			 conf_slot; /**< Slot # in conference bridge.	    */
     pjsip_evsub		*xfer_sub;  /**< Xfer server subscription, if this
 					 call was triggered by xfer.	    */
-    pjmedia_transport	*med_tp;    /**< Media transport.		    */
+    pjmedia_transport	*med_tp;    /**< Current media transport.	    */
+    pjmedia_transport	*med_orig;  /**< Original media transport	    */
     pj_timer_entry	 refresh_tm;/**< Timer to send re-INVITE.	    */
     pj_timer_entry	 hangup_tm; /**< Timer to hangup call.		    */
     pj_stun_nat_type	 rem_nat_type; /**< NAT type of remote endpoint.    */
@@ -313,12 +314,14 @@
  * Media channel.
  */
 pj_status_t pjsua_media_channel_init(pjsua_call_id call_id,
-				    pjsip_role_e role);
+				     pjsip_role_e role,
+				     int security_level);
 pj_status_t pjsua_media_channel_create_sdp(pjsua_call_id call_id, 
 					   pj_pool_t *pool,
+					   const pjmedia_sdp_session *rem_sdp,
 					   pjmedia_sdp_session **p_sdp);
 pj_status_t pjsua_media_channel_update(pjsua_call_id call_id,
-				       const pjmedia_sdp_session *local_sdp,
+				       pjmedia_sdp_session *local_sdp,
 				       const pjmedia_sdp_session *remote_sdp);
 pj_status_t pjsua_media_channel_deinit(pjsua_call_id call_id);